A) Field of the Invention
The present invention relates to a voice synthesizing apparatus, and more particularly to a voice synthesizing apparatus for synthesizing human singing voice.
B) Description of the Related Art
Human voice consists of phones or phonemes that consists of a plurality of formants. In synthesis of human singing voice, first, all formants constituting each of all phonemes that human can speak are generated to form necessary phones. Next, a plurality of generated phones are sequentially concatenated and pitches are controlled in accordance with the melody. This synthesizing method is applicable not only to human voices but also to musical sounds generated by a musical instrument such as a wind instrument.
A voice synthesizing apparatus utilizing this method is already known. For example, Japanese Patent No. 2504172 discloses a formant sound generating apparatus which can generate a formant sound having even a high pitch without generating unnecessary spectra.
It is known that the formant frequency depends upon a pitch. As disclosed in JP-A-HEI-6-308997, a database storing several phonemes at each pitch is used to select proper phoneme pieces in accordance with the voice pitch.
Since such a conventional database requires that each phoneme consists of several phoneme pieces that have different pitches, the size of the database becomes relatively large.
Further, since it is necessary to derive phoneme pieces from voices vocalized at a number of different pitches, it takes a long time to configure the database.
Furthermore, since the formant frequency does not depend only upon the pitch, but it depends also upon other parameters such as dynamics, the data amount increases in the unit of square and cube.